Energy Savings on or off with Fujitsu Heat Pump

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Forums › Finance and wealth management › Energy Savings on or off with Fujitsu Heat Pump

ProfessorAndoheb

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#181136 4-Oct-2015 02:40

O most noble ones!
My question is regarding the Energy Savings settings on my Fujitsu Wall Mounted Heat Pump. I'm wondering if the Energy Savings should be left on or off.
As you folks no doubt know, Energy Savings switched on means if no one is present in the house, the temperature will lower to supposedly save cost. When happy people barge into the house, then the temperature will automatically rise. This is "supposed" to save energy.
I think I was informed to leave that feature off because it cost more to have the Pump work to heat the house up again rather than keeping it at a constant temperature.
Your advice will be appreciated.
(For those who cannot see this posting, please contact one of the moderators)

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Mad Scientist
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#1399545 4-Oct-2015 07:11

It depends.

On many factors.

If your house is perfectly insulated, it doesn't matter when it puts out the heat, when you are away or when you are back, all the heat is retained at all times. In such scenario it depends of the efficiency of the heat pump at various outside ambient temperature, what it does at min output vs medium vs high. So nobody knows.

If your house is poorly insulated, the heat pump serves to heat the Neighbourhood. So it wastes heat when you are not around. The rate of heat waste or loss is proportional to the gradient ie difference between your house and your neighbourhood. By reducing the target temperature, you reduce the heat difference or gradient so the waste is less when you are not around.

You cannot lose with the second option.

ProfessorAndoheb

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#1399547 4-Oct-2015 07:18

This is an interesting reply. Thank you for this. The house is insulated well & was so for electric heat, although we've never used it.
But I'm thinking, if the temperature drops say, 4 degrees, then the Pump has to work harder (so I've been told) to get that temperature back up there to where I want it. Again, I've been told that it's easier on power to have the heat where one wants it and retain it instead of working to get it back up there. Is it not like having a car hurdling down the road at a steady 100 kilometers per hour; thus it is easier on gas instead of slowing down to say 30 kilo's per hour and then having to work the engine to get it back up to 100 kilo's per hour.
Would this make sense to you or am I in complete error?

nakedmolerat

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#1399549 4-Oct-2015 07:26

Many articles has been written in the past including tests by Consumer.

The advice/recommendation is to switch off completely when not in use.

On a curious note, where are you in the country? It has been warm here in Auckland since Spring started!

timmmay

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#1399550 4-Oct-2015 07:33

Unless you have a super insulated house my gut feeling, based on years of owning heat pumps, is it will cost you a lot more to leave it on all the time. The only way to know for sure is to try it in similar weeks (not just days) with similar weather.

ProfessorAndoheb

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#1399551 4-Oct-2015 07:35

I'm on the Eastern side of Canada. It's not cold cold yet but it's cooling off just the same. The guys who sold us the Pump said it's better to leave it on all the time for the same reason & illustration I used about the car thingy.

nakedmolerat

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#1399558 4-Oct-2015 08:00

Ok. Now that we know you're in Canada - things might be a bit different there. It's paid to check what the local advice is.

You're correct that the pump is less efficient when the outside temperature drops below 4 degrees

timmmay

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#1399560 4-Oct-2015 08:25

Being in Canada was pretty important information, and the temperatures you experience would be important too. If you post on a New Zealand forum the assumption is you're in New Zealand unless you say otherswise (though anyone is of course welcome), and NZ temperatures are relatively similar across the country.

I imagine that in Canada they're pretty good at insulation. Given the temperatures you face perhaps you do need your heating on 24/7, just on lower when people around around.

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ProfessorAndoheb

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#1399574 4-Oct-2015 09:03

I wasn't for whatever reason, aware I was on a New Zealand forum. You could have knocked me over with a tombstone when I realized this. Sorry about not saying where I was from, but thinking I was on an American forum ... well, what else can I say!!! :-}

timmmay

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#1399575 4-Oct-2015 09:08

America is a different country from Canada too ;)

I really think asking a local expert would be the best approach. Actually ask at least two, if they disagree keep asking until you get a clear majority. If you don't get a majority try it out for yourself :)

ProfessorAndoheb

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#1399577 4-Oct-2015 09:11

Good advice. Thank you so much for the replies. :-)

bfginger

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#1402066 7-Oct-2015 22:46

Most heat pump models will either struggle to run when it's really cold like -20 celsius or will run with not much more efficiency than direct electric heating. Many models will automatically shut down when it goes below a threshold temperature for nominal self protection though older models may not do that. Weaker models may not cope with 0 celsius if it's damp and spend most of the time in defrost mode. So if your house is well insulated it may be more efficient for it to operate outside of the coldest times of day. High humidity frosting is often a bigger problem than drier but lower temperatures so in areas with very low humidity the cold may not be as much of an issue.

Aren't air to air minisplit heat pumps rare as heat sources in Canada?

https://www.youtube.com/watch?v=l_7KKyuwlOM

ProfessorAndoheb

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#1402247 8-Oct-2015 10:39

Heat Pumps have been around here for years although I wasn't aware of them till of late. Now in these parts, it's almost a fad. They're being installed fast and furious!

ProfessorAndoheb

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#1403172 9-Oct-2015 17:50

Just for a downdate, excuse me, I mean an update. The ecstatic folk who sold me this unit, suggest to leave the Energy Savings on. I had thought it was told me the opposite but for the second time in my life, I was wrong.
This makes sense since both my wife & I are gone most of the day and sleep most of the night. So now all those who have been impatiently waiting for this reply, can rest in peace & now enjoy a moment of silence.
Thank you for the earlier replies. Thank you very much! Huh-ho-hoooo!!!

Batman

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#1403205 9-Oct-2015 18:59

I have 8 of these things in my house.

timmmay

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#1403208 9-Oct-2015 19:02

joker97: I have 8 of these things in my house.

Canadians?

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